package com.dhj.jvmstudy.chapter02;

import java.io.FileNotFoundException;

/**
 * 自定义类加载器
 */
public class CustomClassLoader extends ClassLoader {

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        try{
            byte[] result = getClassFromCustomPath(name);
            if(result == null){
                throw new FileNotFoundException();
            }else {
                return defineClass(name, result, 0, result.length);
            }
        }catch (FileNotFoundException e){
            e.printStackTrace();
        }

        throw new ClassNotFoundException(name);
    }

    /**
     * 将字节码文件转成二进制码流
     */
    private byte[] getClassFromCustomPath(String name){
        // 从自定义路径中加载指定类，细节略
        // 如果指定路径的字节码文件是加密的话，则需要在此方法中做解密操作。
        return null;
    }

    public static void main(String[] args) {
        CustomClassLoader customClassLoader = new CustomClassLoader();
        try {
            Class<?> clazz = Class.forName("One", true, customClassLoader);
            Object obj = clazz.newInstance();
            System.out.println(obj.getClass().getClassLoader());

        }catch (Exception e) {
            e.printStackTrace();
        }
    }

}
